1. Field of the Invention
The present invention relates to an image reading system and an image reading method that read an image of an original, and a program for implementing the method.
2. Description of the Related Art
Conventionally, there has been known an image reading apparatus of this kind that has both the function of reading an image (reflective original image) of an original reflected from the original and the function of reading an image (transparent original image) of the original transmitted through the original. The image reading apparatus reads an image of an original according to selected one of the two functions, using an image sensor, to covert the read image into an electric signal, and digitizes the electric signal into digital data using an A/D converter to send the data to an external apparatus. A preview image of an image obtained according to each of the functions is displayed on driver software operating on the external apparatus.
Such an image reading apparatus is capable of reading images from both the originals of a positive film and a negative film, as described e.g. in Japanese Laid-Open Patent Publication (Kokai) No. 2001-144973. However, the positive film and the negative film are quite different in characteristics from each other, and therefore to obtain a preview image, it is necessary to read an image by a reading method suited to the characteristics of the film as the original. There has already been known an image reading apparatus which is capable of reading images of the two different types of films by the respective reading methods suited to the characteristics of the positive film and those of the negative film.
In the conventional image reading apparatus, however, as mentioned above, to obtain a preview image, it is necessary to read an image by a reading method suited to the type (film characteristics) of a film set in the apparatus.
For example, in the case where a user erroneously pre-scans a positive film to display a preview image with the settings suitable for a negative film, the displayed scanned image is excessively bright. Further, the scanned image is converted into a negative image, so that a totally dark preview image is displayed. On the other hand, in the case where a user erroneously pre-scans a negative film with the settings suitable for a positive film, the displayed scanned image has insufficient brightness, and the scanned image is not subjected to negative-to-positive conversion, so that the dark negative image is displayed as it is.
In either of the cases, the user needs to change the settings to a suitable film and then carry out pre-scanning again so as to display a proper preview image, which is troublesome to the user.